The container for HTTP callshttp_call is the runtime container for HTTP method calls. It contains
the request message, the response message, and the current transmission
status.

In previous versions of netclient, this class type was called
message. This was quite inexact because this class embraces both
messages that are part of a call.

Incompatible changes:

using_proxy has been removed. This simply isn't a property of
an individual call.

get_req_uri has been removed from the public interface for similar
reasons.

The request and response messages are now primarily stored as
Netmime.mime_header and Netmime.mime_body objects. The old
style access methods remain in the API for now. The advantage is
that it is possible to use external files as body containers.

There are two request headers, `Base and `Effective.

Call State

methodis_served : bool

true if request/response cycle(s) have been finished, i.e. the
call was successful, or a final error state has been reached.

The whole header of the request. Users of this class should only
modify the `Base header. After the call has been processed,
the `Effective header contains the version of the header that has
actually been transmitted.

The user should set the following headers:

Content-length: Set this to the length of the request body
if known. (The client falls back to HTTP 1.0 if not set!)

Content-type: Set this to the media type of the request body

Expect: Set this to "100-continue" to enable a handshake before
the body is sent. Recommended for large bodies.